BMR & Calorie Calculator
Free BMR and calorie calculator. Find your basal metabolic rate and daily calorie needs (TDEE) for maintenance, weight loss and gain using the Mifflin-St Jeor formula.
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Free BMR & Calorie Calculator
This free online BMR calculator works out how many calories your body burns at rest and how many you need each day to maintain, lose or gain weight. It uses the trusted Mifflin-St Jeor equation, supports both metric (cm, kg) and imperial (feet/inches, pounds) units, and shows your maintenance calories (TDEE) along with suggested targets for weight loss and weight gain. It’s completely free, needs no sign-up, and runs entirely in your browser — your details are never uploaded.
How to use the BMR calculator
- Choose your unit system: Metric (cm, kg) or Imperial (ft/in, lb).
- Select your gender and enter your age.
- Enter your height and weight in the boxes shown.
- Pick the activity level that best matches your typical week.
- Click Calculate to see your BMR, maintenance calories and weight-loss or gain targets.
What is BMR and TDEE?
Your Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest just
to keep you alive — powering your heart, lungs, brain and other organs. It is the single biggest part of your
daily calorie needs. This tool estimates BMR with the Mifflin-St Jeor equation, which is widely
regarded as one of the most accurate formulas for healthy adults. For men it is
10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5, and for women the final
number is −161 instead of +5.
Your Total Daily Energy Expenditure (TDEE) is your BMR multiplied by an activity factor that accounts for movement and exercise: 1.2 for sedentary, 1.375 for lightly active, 1.55 for moderately active, 1.725 for very active, and 1.9 for extremely active. TDEE is roughly the number of calories you need to maintain your current weight. To lose weight you eat in a calorie deficit (fewer calories than your TDEE); to gain weight you eat in a calorie surplus. A deficit of about 500 calories per day equals roughly half a kilogram of fat loss per week, since around 7,700 calories are stored in a kilogram of body fat.
These figures are estimates, not medical advice. Real calorie needs vary with body composition, genetics, health conditions and more. Very low calorie targets are floored to a safe minimum, but you should always check with a doctor or registered dietitian before starting a serious diet or exercise plan.